Evolution and speciation

Correct answer: A. Speciation

The formation of a new species is called speciation. A population may become separated, experience different environmental pressures and genetic variations, and gradually diverge until the groups can no longer reproduce successfully with one another. Therefore option A is correct. Digestion, respiration, and excretion are life processes, but none describes the evolutionary origin of a distinct species.

Correct answer: A. Different changes can accumulate in separated groups

The governing concept is reproductive isolation in evolution. When a population becomes separated, its groups may stop interbreeding regularly. Mutations, inherited variations, natural selection, and environmental pressures can then act differently in each group. Over many generations, the accumulated differences may become so large that the groups can no longer produce fertile offspring together. Thus, separation can contribute to the formation of a new species; it does not make organisms identical, create food, or remove chromosomes.

Correct answer: A. Geographical isolation

The governing concept is speciation, the formation of new species. When a population becomes geographically isolated, its groups have little or no interbreeding. Mutations, variations, genetic drift and natural selection can then act differently in the separated groups. Over many generations, their differences may become large enough to prevent successful reproduction between them. Therefore, geographical isolation is the suitable factor; the other options are unrelated to the origin of species.

Correct answer: A. Charles Darwin

The governing historical concept is Darwin’s theory of evolution by natural selection. Charles Darwin explained that inherited variations can influence survival and reproduction, causing populations to change over many generations. Therefore option A is correct. Gregor Mendel established important principles of heredity, Rutherford contributed to atomic and nuclear science, and Mendeleev developed the periodic arrangement of elements; none is identified with this theory.

Correct answer: A. By accumulating different changes in groups

The governing concept is reproductive or geographical isolation in speciation. When members of one population become separated, the groups may face different climates, foods, predators, or other conditions. Mutations, inherited variations, and natural selection can then produce different changes in each group. Over many generations, the groups may become sufficiently different to form separate species. Thus option A is correct; the other choices do not describe speciation.